Blackboard-rubber



(No Model.) l

G. MUNGEB..

BLAGKBOARD RUBBER. No. 262,818. Patented Aug.15, 1882.

UNITED STATES PATENT EErcE,

GEORGE MUNGER, OF EAST RIVER, CONNECTICUT.

BLACKBOARD-RUBBER.

SPECIFICATION forming part of Letters Patent No. 262,818, dated August 15, 1882.

Application filed May 15, 1882.

To all whom it may concern Be it known that I, GEORGE MUNGER, of East River, in the county of New Haven and State of Connecticut, have invented a new Improvement in Blackboard-Rubbers; and I do hereby declare the following, when taken in connection with accompanying drawings and the letters of reference marked thereon, to be a full, clear, and exact description of the same, and which said drawings constitute part of this specification, and represent, in-

Figure 1, a perspective view of the rubber; Fig. 2, a face View; Fig. 3, a transverse section.

This invention relates to an improvement in the article used in schools and other places for rubbing crayon-marks from blackboards, and commonly called blackbcard-rubbers.7

It is well known that chamois-skin makes the most desirable material for this purpose. Such a rubber was patented to me November 5, 1861, but it is too expensive for general school uses, and generally a fabricated material has been employed which,\vhile very much cheaper, is less durable and not as good a rubber as those made from chamois-skin, for the reason that the chamois-skin more readily takes hold of the crayon on the board and has a capacity of holding the dust to a very much greater extent than the fabric.

The object of my invention is to so combine chamois-skin and fabricated material that the cheap quality ot' the fabric may be added to the better-cleanin g, dust-holdin g, and more durable capacities ot the chamois-skin; and the invention consists in a face for blackboardrubbers constructed from chamois-skin and fabric l combined so as to present both materials to the surface, as more fully hereinafter described.

In the best method of construction known to me I take strips of preferably cotton fabricv and chamois-skin about equal in widthsay about one-half an inch, more or less. Then of these strips I take preferably one of chamoisskin and two of fabric and braid them into a (No model.)

single strand, and this braid I apply to the wood or other back, A, in parallel lines or otherwise, so as to cover the surface of the board, as seen in Figs. 2 and 3. The braids are best secured to the back by means of glue. As represented in Fig. 2, there is one run of the braid B on the outer edge of the back, with two intermediate parallel braids, C; but they may be otherwise applied. This braiding of the material-say three strands-makes every third strand, a, of leather, while the two intermediate strands, b c, are of the Heeey or other suitable material. Thus constructed, all parts of the surface must necessarily wear together, because the fabric cannot wear away any faster than the leather. All must wear together on the plane surface ot' the board. The leather then serves not only as a part of the rubber, but to prevent hard wear of the fabric, which would necessarily soon harden without the leather, and because of the light wear which comes upon the fabric thus protected by the leather the iieecy surface or character of the fabric is retained, and the rubber, from actual test, will wear very much longer than a rubber wholly of fabric. The little additional costdue to the use of the leather is more than compensated for in the increased wear.

While I prefer braiding strips of fabric and chamois-skin together, as described, the skin and fabric maybe otherwise combined-as, for illustration, in alternate strips or in tufts made from strips of skin and fabric. I therefore do not wish to be understood as limiting my invention to the skin and fabric as braided.

I claim- A blackboardrubber havingits rubbingsurface composed of combined chamois-skin and fabric, so as to present the two materials to the working-surface, substantially as described.

GEO. MUNGER.

Witnesses:

T. F. LEETE, GHAs. N. MURRAY. 

